What is the normal arterial blood pH range?

• A. 7.15 - 7.35
• B. 7.45 - 7.55
• C. 7.35 - 7.45
• D. 7.65 - 7.75

Answer: (C)

Normal arterial pH sits in a very tight window because enzyme activity and many physiological processes depend on it functioning properly. The typical arterial pH range is about 7.35 to 7.45. Values below this indicate acidemia, where the blood is too acidic for optimal cellular function, while values above indicate alkalemia, where the blood is too basic. The body keeps this balance through buffering systems, and by adjusting respiration (CO2 removal) and renal function (bicarbonate and hydrogen ion handling). In practice, when you interpret a blood gas, you assess the pH alongside PaCO2 and bicarbonate to see if a disturbance is respiratory or metabolic and whether compensation is occurring.